Closure seal with semi-adherent and removable liner



June 21, 1966 H. E. BROCKETT 3,257,021

CLOSURE SEAL WITH SEMI-ADHERENT AND REMOVABLE LINER Filed June 4, 1963 BY M @5 7 4- 1 ATTORNEYS .operations.

United States Patent Ice nental Can Company, Inc., New York, N.Y., a corporation of New York Filed June 4, 1963, Ser. No. 235,315

11 Claims. (Cl. 215--39) This invention relates to closures having a rigid shell structure and a sealing liner or cushion therein, and is more particularly concerned with the provision of indicia upon the liner and whereby the liner may be detached from the shell and employed to show the identification of the closure without employment of the total closure assembly.

Such closures are useful in cases where the bottler or seller has a promotional campaign depending upon proof of use of a product: and where attention to a complaint as to the product requires knowledge of lot number, date, or other identification of the goods. In the past, such campaigns or complaints with beverages or the like, bottled with crown closures, has required the employment of the entire crown closures; with the difficulty that the crown shells are bulky and difficult to mail, and have caused damage to mail cancelling machines when enclosed in an envelope as is usual.

The crown closures of present commerce are made with the sealing liner tightly adherent to the shell. The usual practice is to provide an all-over lacquer or enamel coating at one face of the metal stock sheet, and to print the bottlers name etc. on the other face with pigmented enamels, so that the sheet has a number of such printings thereon. The individual shells are then blanked out and formed into caps with corrugated skirts by punch press Liners are then applied. In one practice, cork disks. are introduced after depositing an adhesive such as albumin.- In another practice, a measured quantity of plastisol or other elastomer-providing substance is introduced and 'then hot-molded to provide a desirable sealing gasket which possesses a firm bond to the inner lacquer coating.

According to the instant invention, the internal lacquer layer is selected and applied to obtain'excellent adhesion to the metal of the shell and to obtaina low order of adhesion of the indicia and sealing liner at the lacquer so that the crown closure will go through the steps of manufacture and use satisfactorily. When proof of use is tobe supplied by a customer, the liners with the indicia adhered to them can be readily peeled from the shells and shipped as thin flexible bodies which can be handled in ordinary envelopes.

Illustrative practice of the invention is shown on the accompanying drawings, in which:

FIGURE 1 is a perspective View showing how multiple patterns of indicia can 'be printed upon the sheet stock prior to the blanking and forming of the shells;

FIGURE 2 is a diametrical sectional view through a lacquered crown shell according to this invention;

FIGURE 3 is a like View, with a formed liner in the shell;

FIGURE -4 is a plan view into the open face of a crown shell as in FIG. 3, with a transparent liner in place;

FIGURE 5 is a plan view like FIGURE 4, with a liner present as in FIGURE 3, with an opaque liner;

FIGURE 6 is a perspective view of a transparent liner according to this invention, after removal from its shell,

3,257,021 Patented June 21, 1966 and with a sector cut away to show the thicknesses of the liner;

FIGURE 7 is a like view of an opaque liner.

In the illustrative practice of the invention, a metal sheet 10, FIG. 1, has an all-over lacquer coating 11 on its upper face, portions of which will provide the inner surfaces of the crown shells, and a plurality of printed indicia 12 are printed thereon; i.e. by use of a silk screen and a silk screen type ink, 'by off-set lithography, by rotogravure, or by other means. The other or bottom face of the sheet 10 can be printed for the indicia which are to appear on the outer surface of the crown shells.

It is preferred to apply the two lacquer or enamel coatings and then cure the same by baking before printing thereon; and to make the sheet again to set the printed indicia. V

The lacquer for the top surface 11 in FIG. 1' can be of the usual type used for the type of liner employed in the crown. A suitable lacquer for a vinyl resin plastisol is a solvent solution containing a vinyl chloride-vinyl acetate copolymer with a small amount of maleic anhydride in the vinyl copolymer and also containing a phenolic resin modifier. Such a lacquer applied to metal and baked at 350 F. for 10 minutes gives good adhesion of a hot shaped vinyl chloride resin plastisol liner but the adhesion of the liner is markedly reduced if the lacquer is baked at 400 F. i

The indicia can be provided by a pigmented plastisol, e.g. particles of polyvinyl chloride resin suspended in a lasticizer such as diocyl phthalate and/or epoxidized oils, with or without tackifi-ers such as methyl rosin ester and epoxidized polybutadiene, together with organometallic stabilizers and organic and/or inorganic pigments such as titanium dioxide, carbon black, iron oxides, organic lake colors, quinacridones, molybdate orange. The plastisol can be printed over the lacquer by silk screening, rotogravure, or offset lithography and baked to fuse or flux the plastisol print with a typical bake of 5 minutes at 375 F. The printed sheet, after cooling, can be punched into crown sheets and then made into caps as shown in FIGURES 2-5.

The individual areas of FIG. 1 provide shells as in FIGS. 2 and .4, with the metal shell having a bottom or dome 15 and the corrugated skirt 16. The internal lacquer layer 11 covers the metal, and has local cured applications 12 of ink constituting the indicia. The outer enamel is a layer 17. The shells are then provided with liners or cushions 20 as in FIGURES 3, 6 and 7, which may have a thicker annular portion 21 for engagement with the container lip and a thin central portion 22. Such liners may be formed by depositing a measured quantity of plastisol in the shell and forming the same by a shaping punch while heating to cure or elfect inter-dissolution of the plasticizer liquid and the resin particles into one another. Useful plastisols comprise fine granules of polyvinyl chloride suspended in a plasticizer such as dioctyl phthalate: such plastisol is a viscous liquid or paste at room-temperature and up to about F., but quickly fuses at an elevated temperature such as 325 to 375 F. Such a plastisol can form a transparent elastic cushion upon curing and therewith the indicia 12 will be visible therethrough; and the appearance of the indicia, upon looking into the closure cap, will remain as shown in FIG. 4. When the plastisol contains a coloring or opaquing agent so that the indicia are not visible therethrough as in FIG. 4, it is preferred to print the indicia in reverse,.as shown in FIG. 5. In each case, the cured plastisol forming the expos d surface of the liner 22 acts to prevent contents of the container from coming in contact with the ink substances forming the indicia 12. When the liner Z is of transparent material, and is removed, the lettering etc. appears in reverse when viewed from the back, that is, at the surface which has been in separable adherence with the metal shell: such is shown in FIG. 6, and it will be understood that when viewed from the opposite side, the indicia are clearly visible in normal order. When an opaque liner is provided, over indicia printed in reverse as in FIG. 5, the removed liner has the indicia readable in normal order, as shown in FIG. 7. In each instance, the customer and the company employees can read the indicia without difficulty.

Such crown closures may be applied to and their corrugated skirts cri-mped upon containers in the usual way. The liner with the indicia adhering to it can be readily peeled from the lacquered shell so that the liner is identified.

When proof of the consumers aquisition for use of the contents is required, the liner 26 can be peeled from the shell as an integral article having the indicia at the face thereof which was in contact with the lacquer. Such a removed cushion or liner is shown in FIGURE 6, Where a sector has been cut away to show the section of the article: noting that in practice the diameter can be about one inch, the center thickness 2 to 10 mils, and the thickness at the annulus 21 around to mils. Such an article is highly flexible, and approximately of the thickness of a cardboard which can be mailed in an ordinaryenvelope without the aforesaid ditficulties.

With the employment of transparent liner materials, the preference is to have letters and numbers appear in normal arrangement for viewing through the liner, as shown in FIGURE 4: and hence in reversed arrangement when the bottom of the liner is viewed as in FIGURE 6.

This is not compulsory: and with opaque liner materials,

it is preferred to print in reverse upon the interal lacquer coating as shown by dotted lines in FIGURE 5, so that the letters etc. appear for direct reading on the bottom of the liner when removed from the shell, as in FIG- URE 7.

In present practice, the indicia 12 are formed by printing with an ink competent of bonding to the liner material and of color distinctive therefrom: with the printing through an appropriate silk screen stencil, by rotogravure, or by ofliset lithography. Such plastisol can be of the same resin: plastcizer composition as the plastisol employed for the liner 20, with inclusion of a dye or pigment so it appears clearly distinct from the liner 20 and, with transparent liners, preferably likewise distinct from the internal laquer on the shell.

Examples of plastisols useful for the liner composition and the indicia are those in which the resin particles are of vinyl chloride polymers such as the homopolymers and its copolymers with ethylenically unsaturated compounds including other vinyl monomers such as the acetate, vinylidene monomers such as the chloride, unsaturated organic acid monomers such as maleic anhydrides, and the mixtures of such monomers. The liquid plasticizer in which the particles are dispersed can be an alkyl phthalate such as dioctyl or an epoxidized oil such as linseed or a combination of plasticizers.

Thus, the sealing liner composition can be composed in parts by weight, of:

4. A compatible indicia composition can be, also in parts by weight:

It is obvious that the illustrative embodiments are not restrictive, and that the invention can be employed in many ways Within the scope of the appended claims.

What is claimed is:

1. A crown closure comprising an internally lacquered rigid shell, a cushion liner therein, and material providing indicia between the lacquer and the liner and adherent to both of the same, the adhesion between indicia and liner being greater than the adhesion between the indicia and the lacquer whereby the linear with the indicia adhering thereto may be peeled from the lacquered rigid shell.

2. The closure as in claim 1, in which the indicia are in reversed order on the lacquer, in which the cushion liner is opaque, and in which the indicia are in normal reading order when viewed at the back of the removed liner.

3. The closure of claim 1, in which the liner is of transparent material and the said indicia comprise printed matter adherent to the rear surface of the liner.

4. The closure as in claim 3, in which the indicia are in normal reading order when viewed through the trans parent liner.

5. The method of making a crown closure which comprises applying a lacquer and indicia to one face of a metal sheet, forming the sheet into a crown shell with the said face inside the same, depositing a thermoplastic mass in the shell and shaping the same into an elastic liner under heat and pressure and eflecting adhesion of the liner to said lacquer and indicia, and therewith establishing the adhesion between the lacquer and indicia at a lesser strength than the adhesion between the liner and indicia.

6. The method as in claim 5, in which the indicia are applied in reverse reading order on the lacquer, and the thermoplastic mass is opaque.

7. The method of claim 5, in which the thermoplastic mass is a plastisol.

8. The method of claim 5, in which the thermoplastic mass is selected to produce a transparent liner.

9. The method as in claim 8, in which the indicia are applied in normal reading order on the lacquer.

10. The method of making a crown closure which comprises applying a lacquer to one face of a metal sheet and then overbaking the same, applying a plastisol indicia layer to said lacquer and heating to completely fuse the same, forming the sheet into a crown shell with the lacquered face innside the same, depositing a plastisol liner in the shell and molding under pressure and heat to completely fuse and shape the liner and effect adhesion of the liner to said lacquer and indicia layer and therewith establishing the adhesion between the lacquer and indicia layer at a lesser strength than the adhesion between the liner and the indicia layer.

11. A crown closure comprising a rigid metal shell formed from a metal sheet that has been coated with lacquer and which is then overbaked, indicia material being applied to said lacquer prior to the forming of the metal sheet into said rigid metal shell, a plastisol liner molded in situ under heat and pressure in the shell such that in the completed crown closure the adhesion of the indicia material to the liner is greater than the adhesion of the indicia material to the lacquer, whereby upon removal of the liner from the lacquered crown closure, the

lacquered crown closure.

5 6 indicia material adheres to the liner instead of to the 3,072,249 1/ 1963 Tritsch 20656 3,080,082 3/ 1963 Glasbremmer. References Cited by the Examiner 1 302 276 H E PATENTS 7 9 2 France. UNITED STATES PATENTS 5 560,184 3/1944 Great Britain. 9/ 1925 Russell 810,786 3/1959 Great Britain. 10/1927 Copenian 264238 4/1929 Stratford 2151 THERON E. CONDON, Primary Examiner. Ryder gg 10 J. M. CASKIE, Assistant Examiner.

Isele-Aregger 215- 

1. A CROWN CLOSURE COMPRISING AN INTERNALLY LACQUERED RIGID SHELL, A CUSHION LINER THEREIN, AND MATERIAL PROVIDING INDICIA BETWEEN THE LACQUER AND THE LINER AND ADHERENT TO BOTH OF THE SAME, THE ADHESION BETWEEN INDICIA AND LINER BEING GREATER THAN THE ADHESION BETWEEN THE INDICAI AND THE LACQUER WHEREBY THE LINEAR WITH THE INDICIA ADHERING THERETO MAY BE PEELED FROM THE LACQUERED RIGID SHELL. 